Substantially cylindrical composite articles and fan casings

ABSTRACT

Articles having substantially cylindrical bodies including a plurality of circumferential layers, each layer having at least one ply of material, the material comprising a weave fabric, a non-crimp fabric, or a combination thereof.

TECHNICAL FIELD

Embodiments described herein generally relate to composite articleshaving a substantially cylindrical body. More particularly, embodimentsherein generally describe composite fan casings having a substantiallycylindrical body including a plurality of circumferential layers.

BACKGROUND OF THE INVENTION

In gas turbine engines, such as aircraft engines, air is drawn into thefront of the engine, compressed by a shaft-mounted compressor, and mixedwith fuel in a combustor. The mixture is then burned and the hot exhaustgases are passed through a turbine mounted on the same shaft. The flowof combustion gas expands through the turbine, which in turn spins theshaft and provides power to the compressor. The hot exhaust gases arefurther expanded through nozzles at the back of the engine, generatingpowerful thrust, which drives the aircraft forward.

Because engines operate in a variety of conditions, foreign objects maysometimes undesirably enter the engine. More specifically, foreignobjects, such as large birds, hailstones, sand and rain may be entrainedin the inlet of the engine. As a result, these foreign objects mayimpact a fan blade and cause a portion of the impacted blade to be tornloose from the rotor, which is commonly known as fan blade out. Theloose fan blade may then impact the interior of the fan casing causing aportion of the casing to bulge or deflect. This deformation of thecasing may result in increased stresses along the entire circumferenceof the fan casing.

In recent years composite materials have become increasingly popular foruse in a variety of aerospace applications because of their durabilityand relative light weight. Current composite technology typically usesmaterial having a tri-axial braid. As the name suggests, tri-axial braidgenerally consists of three fiber tows interwoven to form a braided plyof material. Although braided composite materials can provide superiorweight and impact resistance properties when compared to non-compositematerials, improvements can still be made.

For example, tri-axial braid material can often support only a definedmaximum amount of applied tension beyond which the fiber architecture ofthe material will undesirably distort. Moreover, layered plies oftri-axial braid material can exhibit a degree of interlocking, which canmake delamination difficult to ensure during impacts. This can result ina limited degree of impact energy dissipation. Additionally, thecomplexity of the braid design can make such materials costly.

Accordingly, there remains a need for articles, and in particularcomposite fan casings, made from more cost effective materials that canprovide the desired delamination while supporting increased tension.

BRIEF DESCRIPTION OF THE INVENTION

Embodiments herein generally relate to articles comprising asubstantially cylindrical body including a plurality of circumferentiallayers, each layer having at least four plies of a material, a first plyand a fourth ply comprising a weave fabric including 0°/90° fiber towsand a second ply and a third ply comprising a non-crimp fabric includingθ and −θ fiber tows wherein θ is from about 10° to about 80°.

Embodiments herein also generally relate to articles comprising asubstantially cylindrical body including a plurality of circumferentiallayers, each layer having at least four plies of a material, a first plyand a fourth ply comprising a weave fabric including 0°/90° fiber towsand a second ply and a third ply comprising a weave fabric including45°, and −45° fiber tows.

Embodiments herein also generally relate to fan casings comprising asubstantially cylindrical body including a plurality of circumferentiallayers, each layer having at least one ply of material, the materialcomprising a non-crimp fabric.

These and other features, aspects and advantages will become evident tothose skilled in the art from the following disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the invention, it is believed that theembodiments set forth herein will be better understood from thefollowing description in conjunction with the accompanying figures, inwhich like reference numerals identify like elements.

FIG. 1 is a schematic cut away view of one embodiment of a gas turbineengine in accordance with the description herein;

FIG. 2 is a schematic view of one embodiment of a tool having asubstantially cylindrical shape in accordance with the descriptionherein;

FIG. 3 is a schematic close-up view of one embodiment of a materialcomprising a weave fabric including 0°/90° fiber tows in accordance withthe description herein;

FIG. 4 is a schematic close-up view of one embodiment of a materialcomprising a weave fabric including 45°, −45° fiber tows in accordancewith the description herein;

FIG. 5 is a schematic cut away view of one embodiment of a materialcomprising a non-crimp fabric including θ and −θ fiber tows wherein θ is45° in accordance with the description herein;

FIG. 6 is a schematic cut away view of one embodiment of a materialcomprising a non-crimp fabric including 0°, 60°, −60° fiber tows inaccordance with the description herein;

FIG. 7 is a schematic cut away view of one embodiment of a materialcomprising a non-crimp fabric including 90°, 30°, −30° fiber tows inaccordance with the description herein;

FIG. 8 is a schematic perspective view of one embodiment of a toolhaving at least one ply of material, and optionally four plies, wrappedconcurrently thereabout in accordance with the description herein;

FIG. 9 is a schematic perspective view of one embodiment of a fan casingpreform in accordance with the description herein;

FIG. 10 is a schematic partial, cross-sectional view of one embodimentof a tool with an end flange shoe having a fan casing preform with anend flange and a contour wrapped thereabout; and

FIG. 11 is a schematic perspective view of one embodiment of a fancasing having a contour and a first and second end flange in accordancewith the description herein.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments described herein generally relate to articles, and inparticular composite fan containment casings (herein “fan casings”),having a substantially cylindrical body including a plurality ofcircumferential layers, each layer having at least one ply of material,the material comprising a weave fabric, a non-crimp fabric, or acombination thereof.

While embodiments herein may generally focus on composite fan casingsfor gas turbine engines, it will be understood by those skilled in theart that the description should not be limited to such. Indeed, as thefollowing description explains, the following description is equallyapplicable to any composite article having a substantially cylindricalbody.

Turning to the figures, FIG. 1 is a schematic representation of oneembodiment of a gas turbine engine 10 that generally includes a fanassembly 12 and a core engine 14. Fan assembly 12 may include a fancasing 16 and an array of fan blades 18 extending radially outwardlyfrom a rotor disc 20. Core engine 14 may include a high-pressurecompressor 22, a combustor 24, a high-pressure turbine 26 and alow-pressure turbine 28. Engine 10 has an intake end 30 and an exhaustend 32.

To make the articles described herein, at least one ply of material canbe wrapped about a substantially cylindrically shaped tool to produce aplurality of circumferential layers, which may then be treated with aresin and cured, as set forth herein below.

Initially, as shown in FIG. 2, a tool 34 having a substantiallycylindrical shape can be provided. See, for example, U.S. PatentApplication No. 2006/0134251 to Blanton et al. As used hereinthroughout, the term “substantially cylindrical” means generally havingthe shape of a cylinder, either with or without a contour, as explainedherein below. Tool 34 may be internally solid, hollow, or somecombination thereof.

At least one ply of a material may then be provided for wrapping abouttool 34, as described herein below. The ply of material may comprise aweave fabric, a non-crimp fabric, or a combination thereof. As usedherein “weave fabric” refers to fabric that is formed on a loom, orother like device, by interlacing two sets of fiber tows together. Weavefabric can comprise a variety of patterns, including, but not limitedto, plain weave, twill weave, and four-harness weave. “Non-crimp fabric”refers to fabric that is formed by stacking one or more plies ofunidirectional fibers and then stitching the layers together. Theunidirectional fibers of non-crimp fabric may be oriented in a varietyof ways to satisfy design requirements.

For example, ply of material 36 may comprise a weave fabric including0°/90° fiber tows 38 (as shown in FIG. 3) or 45° and −45° fiber tows 38(as shown in FIG. 4). Similarly, ply of material 36 may comprise anon-crimp fabric including θ and −θ fiber tows 38 wherein θ is fromabout 10° to about 80°, and in one embodiment may be 45° (as shown inFIG. 5), 0°, 60° and −60° fiber tows 38 (as shown in FIG. 6) or 90°,30°, −30° fiber tows 38 (as shown in FIG. 7). Those skilled in the artwill understand that because the non-crimp fabric is formed by stitchingtogether stacks of unidirectional fibers, the unidirectional fibers mayhave virtually any angle of orientation desired and should not belimited to the examples provided previously herein.

Regardless of the fabric utilized, or the orientation of the fiber towsof the fabric, in general, the fiber tows may comprise any suitablereinforcing fiber known to those skilled in the art capable of beingcombined with a resin to produce a composite material. In oneembodiment, the fiber tows may comprise at least one of carbon fibers,graphite fibers, glass fibers, ceramic fibers, and aromatic polyamidefibers. Additionally, each fiber tow 38 may comprise from about 3000 toabout 24,000 individual fiber filaments.

Next, as shown in FIG. 8, at least one ply of material 36, a first ply44, may be wrapped about tool 34 from a spool 39 to produce an articlepreform having a plurality of circumferential layers 40. In oneembodiment, the article preform may comprise a fan casing preform 42(shown in FIG. 9). For embodiments in which more than one ply ofmaterial 36 is employed, first ply 44, second ply 46, third ply 48 andfourth ply 50 may be wrapped concurrently about tool 34 from respectivespools 39 to form plurality of circumferential layers 40 of the fancasing preform, as shown in FIG. 8.

To address the previously discussed deficiencies with current compositetechnology, in one embodiment, it may be desirable to wrap at least oneply of material 36 about tool 24, wherein ply of material 36 comprises anon-crimp fabric. In this instance, the non-crimp fabric may comprise0°, 60° and −60° fiber tows (as shown in FIG. 6) or alternately, 90°,30° and −30° fiber tows (as shown in FIG. 7). In an alternateembodiment, it may be desirable to wrap at least four plies of material36 about tool 34, wherein the plies of material comprise either weavefabric or a combination of weave fabric and non-crimp fabric. Moreparticularly, one embodiment may involve providing at least four pliesof a material, the first ply 44 and fourth ply 50 comprising a weavefabric including 0°/90° fiber tows and the second ply 46 and third ply48 comprising a weave fabric including 45° and −45° fiber tows. Analternate embodiment may involve providing at least four plies ofmaterial, the first ply 44 and fourth ply 50 comprising a weave fabricincluding 0°/90° fiber tows and the second ply 46 and third ply 48comprising a non-crimp fabric including θ and −θ fiber tows wherein θ isfrom about 10° to about 80°, and in one embodiment, θ is 45°.

After all desired plies of material 36 have been wrapped about tool 34,the resulting fan casing preform 42 can have a substantially cylindricalbody 52, as shown in FIG. 9.

Optionally, in one embodiment, fan casing preform 42 may be constructedto comprise at least a first end flange 54 that is integral withsubstantially cylindrical body 52. First end flange 54 may beconstructed using tool 34 having at least a first end flange shoe 56 asshown in FIG. 10. Before wrapping the desired ply or plies of material36 about tool 34 having first end flange shoe 56, any 0° fiber towspresent can be removed from a first end portion 58 of the ply ofmaterial 36 having the 0° fiber tows. Alternately, the weave fabric ornon-crimp fabric may be constructed so as to lack 0° fiber tows in thearea that is first end portion 58. By “end portion” it is meant asection running lengthwise along an edge of ply of material 36 thatgenerally corresponds in width to the desired length of the end flange54 it will be used to construct, as shown in FIG. 10.

For example, in plies of material 36 comprising either a weave fabricincluding 0°/90° fiber tows, or a non-crimp fabric including 0°, 60°,−60° fiber tows, the 0° fiber tows can be removed from first end portion58, and the first end portions aligned with the first end flange shoe 56of tool 34. The 0° fiber tows may be removed using any technique knownto those skilled in the art, such as, but not limited to, cutting andpulling the 0° fiber tows from the ply of material at the first endportion 58. Plies of material 36 lacking 0° fiber tows may also bealigned with end flange shoe to aid in the construction of end flange54, and all plies may then be wrapped concurrently about tool 34 untilthe desired thickness is obtained. Those skilled in the art willunderstand that a second end flange 60 may be integrally constructed atthe opposing end of body 52 of fan casing preform 42 using the methodsdescribed previously.

In another embodiment, fan casing preform 42 may comprise a contour 62,as shown in FIGS. 10 and 11. As used herein, “contour” means that atleast a portion of body 52 of the fan casing (preform) comprises a curvethat may be directed inward to, outward from, or some combinationthereof, the plane of body 52. Despite the presence of contour 62, body52 can remain substantially cylindrical. To fabricate a body 52 having62 contour, the tool utilized can comprise the desired contour 62 suchthat as the circumferential layers are layed-up about the tool, thecontour is formed.

Once all desired plies of material 38 have been wrapped about tool 34 toproduce fan casing preform 42, a resin may be applied to the preform tobond the circumferential layer together when cured. Any resin commonlyused by those skilled in the art is acceptable for use herein.Conventional resins commonly used in composite technology can include,but should not be limited to, vinyl ester resins, polyester resins,acrylic resins, epoxy resins, polyurethane resins, and mixtures thereof.Application of the resin may be carried out using any suitable techniqueknown to those skilled in the art, such as resin film infusion (RFI),resin transfer molding (RTM), vacuum assisted resin transfer molding(VARTM), and other like techniques.

Having applies the selected resin, the preform may then be cured usingconventional curing techniques known to those skilled in the art toproduce an article, which in one embodiment is a fan casing 16 havingsubstantially cylindrical body 52, a first end flange 54 and a secondend flange 60, as shown in FIG. 11.

Constructing an article, and in particular a fan casing, using thepreviously described materials and methods can offer several benefitsover current composite technology. For example, because weave fabric andnon-crimp fabric display less fiber undulation than tri-axial braid, thesurface of such fabrics is smoother and less prone to mechanicalinterlocking of successive plies. Less interlocking equates to enhanceddelamination, which can provide for increased energy dissipation afteran impact. Another benefit is that weave and non-crimp fabrics can bemore stable than tri-axial braid and therefore, can support increasedtension without suffering significant distortion to their fiberarchitecture. This ability to support tension allows for tighter wrapsabout the tool and a reduced occurrence of wrinkle formation, which caninterfere with the functioning of the article. Additionally, the lack of0° fiber tows in the end portion of the plies of material can allow forthe construction of integral end flanges in articles comprising weavefabrics and non-crimp fabrics. Having the end flanges integral to thefan casing allows for stronger flanges that can withstand greaterapplied forces when compared to non-integral flanges. Moreover, due tothe manner of construction, weave fabric and non-crimp fabrics can be amore cost effective alternative to tri-axial braid fabric.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope of the inventionis defined by the claims, and may include other examples that occur tothose skilled in the art. Such other examples are intended to be withinthe scope of the claims if they have structural elements that do notdiffer from the literal language of the claims, or if they includeequivalent structural elements with insubstantial differences from theliteral language of the claims.

What is claimed is:
 1. A fan casing comprising: an article preformhaving as substantially cylindrical body and optionally a first endflange, wherein the body includes plurality of circumferential layers,each layer having at least four plies of a material, a first ply and afourth ply comprising a weave fabric including 0°/90° fiber tows and asecond ply and a third ply comprising a non-crimp fabric including θ and−θ fiber tows, wherein θ is from about 10° to about 80°, the end portionof each ply forming the length of the optional end flange, the 0° fibertows being removed from the weave fabric of material of forming the endportion; and a resin, each of the plurality of layers treated with theresin, wherein the resin-treated layers are cured to form the preform.2. The fan casing of claim 1 wherein the fiber tows of each ply compriseat least one of carbon fibers, graphite fibers, glass fibers, ceramicfibers, and aromatic polyamide fibers.
 3. The fan casing of claim 1wherein θ is 45°.
 4. The fan casing of claim 1 wherein at least aportion of the casing comprises a contour.
 5. The fan casing of claim 1further comprising at least a first end flange made by a methodincluding: removing the 0° fiber tows from a first end portion of thefirst ply of material and a first end portion of the fourth ply ofmaterial; wrapping the at least four plies of material concurrently,about a tool having at least first end flange shoe such that at leastthe first end portion if the first ply of material and the first endportion of the fourth ply of material are aligned with the first endflange shoe to produce an article preform comprising at least as firstend flange preform portion; applying a resin to the article preform; andcuring the article preform to produce the fan casing comprising thefirst end flange.
 6. The fan casing of claim 1 wherein θ is 60°.
 7. Thefun casing of claim 1 wherein θ is 30°.
 8. The fan casing of claim 5wherein applying resin to the article preform includes a method selectedfrom the group consisting of resin film infusion, resin transfer moldingand vacuum assisted resin transfer molding.
 9. The fan casing of claim 5wherein removing fiber tows from the first end flange provides a fancasing with increased energy dissipation and reduced wrinkle formation.10. The fan casing of claim 1 wherein the casing further includes asecond flange.
 11. An article comprising: an article preform having asubstantially cylindrical body and optionally a first end flange,wherein the body includes a plurality of circumferential layers, eachlayer having at least one ply selected from the group consisting of anon-crimp fabric, a crimp fabric and combinations thereof; the endportion of each ply forming the length of the optional end flange, the0° fiber tows being removed from the weave fabric of material formingthe end portion; a resin, each of the plurality of layers treated withthe resin, wherein the resin-treated layers are cured to form thepreform, wherein the non-crimp fabric is formed by stacking one or moreplies of unidirectional fiber and stitching the layers together, and theweave fabric includes two sets of fiber tows interlaced together.